If they're re-using maps/models from the previous games they must be reasonably advanced in putting the game together. S.T.A.L.K.E.R. 2 was/is supposed to be PC and console, so I had a hope that if the game was integrating XAudio 2 and XInput libraries (needed for console development), then the game could well be DirectX 11.1, which utilizes both as well as DirectXMath and, by all accounts, provides a reasonable performance boost over DirectX 11.